Leberg P L, Spengler T J, Barrow W C
Department of Biology, University of Southwestern Louisiana, 70504, Lafayette, LA, USA.
Southern Science Center National Biological Service, TAMU-CC, Campus Box 339, 78412, Corpus Christi, TX, USA.
Oecologia. 1996 Apr;106(1):1-7. doi: 10.1007/BF00334401.
Lipid depletion is currently believed to be the primary factor limiting flight duration of migrating birds in North America, while the influence of water loss is thought to be small. Three migrating species of passerines, wood thrush (Hylocichla mustelina), Swainson's thrush (Catharus ustulatus), and summer tanager (Piranga rubra) were captured during the 1993 spring migration just after crossing the Gulf of Mexico and examined for lipid and water depletion. The redwinged blackbird (Agelaius phoeniceus), a winter resident, was examined for comparison. Although some migrants had low levels of fat, most were not seriously fat-depleted and had much higher lipid levels than red-winged blackbirds. Migrants appeared dehydrated, usually having less than 60% body water and significantly less water than the blackbirds. Recaptured wood thrushes had significantly higher mass than when initially captured. Many of these birds were replenishing significant amounts of water, while the acquisition of lipid mass was dependent on the amount of time the birds spent on the study site. Migrants were significantly fatter but had significantly less water mass when captured during unfavorable weather than under favorable conditions. It appears that both dehydration and lipid depletion are major physiological constraints on migrating passerines.
目前认为脂质消耗是限制北美候鸟飞行持续时间的主要因素，而水分流失的影响被认为较小。在1993年春季迁徙期间，三种迁徙的雀形目鸟类，即伍德 Thrush（Hylocichla mustelina）、斯温森 Thrush（Catharus ustulatus）和夏季 Tanager（Piranga rubra）刚穿越墨西哥湾后就被捕获，并检查了脂质和水分消耗情况。作为对照，检查了留鸟红翅黑鹂（Agelaius phoeniceus）。尽管一些候鸟脂肪含量较低，但大多数并未严重脂肪耗尽，且脂质水平比红翅黑鹂高得多。候鸟似乎脱水了，通常体内水分含量不到60%，且水分明显比黑鹂少。重新捕获的伍德 Thrush的体重明显高于最初捕获时。这些鸟中有许多正在补充大量水分，而脂质质量的获取则取决于它们在研究地点停留的时间。与有利条件下相比，在不利天气下捕获的候鸟明显更胖，但水分质量明显更少。看来脱水和脂质消耗都是迁徙雀形目鸟类的主要生理限制因素。
